RU2366797C1 - Method of pressure testing of well head accessory in well - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: invention refers to oil and gas industry, particularly to method of pressure testing of well head accessories in well. The method consists in lowering a packer with a drive on a support pipe at rate not more, than 1 m/sec; the well above the packer is filled with fluid; the support pipe is pressurised at the well head; testing pressure with rate of build up 0.3-0.5 MPa/sec is created inside the well head accessories; these process conditions are held during not less, than 30 minutes; change of pressure is evaluated; the well head accessories are assessed for leak tightness or leakage; pressure in the well head accessories is dropped at rate not more, than 1 MPa/sec; the packer is released; fluid is discharged above the packer into the well; the packer with the drive and the support pipe are removed from the well at rate not more, than 1 m/sec.

EFFECT: increased accuracy of evaluating leak tightness of well head accessories at pressure testing.

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Description

The invention relates to the oil and gas industry and may find application in pressure testing of wellhead valves in the well.

A known method of crimping a fountain "Christmas tree" wellhead equipment production wells. Install the packer in the channel of the head of the tubing without killing the well using a crimping device, which consists of a housing with a nut, a screw with a rod, a packer connected to a screw rod, a rod connected to the packer, a pallet and a helm. The axial movement of the packer along the channels of the stem valves of the fountain Christmas tree is carried out by rotating the housing nut with the control wheel of the device and the head channel of the tubing placed in the adapter of the pipe head is sealed by axial compression of the body of the packer sealing element by rotation of the packer screw, while the packer screw is equipped with rectangular protrusion for transmitting torque during rotation of the rod located inside the screw with the rod and covering the rectangular protrusion of the packer screw, and control the position of the packer during its axial movement along the channels of the stem gate valves is carried out using an indicator of the position of the packer mounted on the end face of the nut fixed to the end of the screw with the rod. The reception of the pressure fluid and its transmission through the openings of the housing into the channels of the gates of the Christmas tree is carried out through a pallet covering the housing of the device and located below the inlet openings (RF Patent No. 2236552, publ. 2004.09.20).

The known method does not describe the crimping modes using the described equipment.

Closest to the proposed invention in technical essence is the wellhead packer, designed to check the tightness of the mouth section of the casing together with blowout equipment. In the wellhead packer, consisting of a body, a seal assembly and a liner, the seal assembly is made of two radial cuffs with collars and gentle outer chamfers for introducing the packer into the wellhead. The cuffs are separated by a washer with bevels geometrically corresponding to the surface of the cuff collars. The washer has fluid supply channels from the upper cuff to the lower. To limit the degree of compression of the cuffs, the spacer sleeve serves as stabilizer stops. The upper stop-stabilizer has channels for supplying fluid from the annulus to the cavity of the upper cuff. The shank is provided with an annular row of threaded radial through holes for installing retaining screws fixing the shank in the annular groove of the housing. The method of crimping wellhead valves is as follows. The packer is lowered on the drill pipe. Create pressure in the annulus. The packer seals the crimping area. After stopping the flow of the crimping fluid, the cuffs take their original form (RF Patent No. 2152506, publ. 2000.07.10 - prototype).

The known method does not describe the conditions for crimping, however, the crimping modes are decisive when making a conclusion about the tightness of wellhead valves.

The proposed method solves the problem of ensuring the reliability of pressure testing of wellhead valves in the well.

The problem is solved in that in the method of crimping wellhead fittings in the well, including lowering the packer with the drive on the support pipe into the well, setting the packer and creating pressure, according to the invention, lowering the packer with the drive on the support pipe is carried out at a speed of not more than 1 m / s, the well the packer is filled with liquid above the packer, the support pipe is sealed at the wellhead, test pressure is created inside the wellhead with a pressure rise rate of 0.3-0.5 MPa / s, technological exposure is carried out for at least 30 minutes, pressure change is evaluated, make a conclusion about the tightness or leaks of the wellhead fittings, depressurize the wellhead with a speed of not more than 1 MPa / s, unpack the packer, drain the liquid above the packer into the well, remove the packer with the drive and support pipe from the well with a speed of not more than 1 m / s .

The features of the invention are:

1. descent of the packer with the drive on the support pipe into the well;

2. setting the packer;

3. creating pressure;

4. descent of the packer with the drive on the support pipe at a speed of not more than 1 m / s;

5. filling the well above the packer with liquid;

6. sealing at the wellhead of the support pipe;

7. creation of test pressure inside the wellhead reinforcement with a pressure rise rate of 0.3-0.5 MPa / s;

8. holding technological exposure for at least 30 minutes;

9. assessment of pressure changes;

10. conclusion on the tightness or leaks of wellhead valves;

11. pressure relief in wellhead valves at a rate of not more than 1 MPa / s;

12. unpacking the packer;

13. draining fluid above the packer into the well;

14. Removing the packer with the drive and the support pipe from the well at a speed of not more than 1 m / s.

Signs 1-3 are common with the prototype, signs 4-14 are the salient features of the invention.

SUMMARY OF THE INVENTION

Wellhead fittings after installation in the well should be pressure tested for maximum working pressure in the production casing. Existing technical solutions for pressure testing of wellhead valves solve the problem only from the point of view of equipment without a description of pressure testing modes. However, the crimping modes are decisive when making a conclusion about the tightness of wellhead valves, i.e. reliability of crimping. The proposed method solves the problem of ensuring the reliability of pressure testing of wellhead valves in the well. The problem is solved as follows.

During pressure testing of wellhead fittings, the packer is driven with the drive on the support pipe at a speed of not more than 1 m / s, the well above the packer is filled with liquid, the support pipe is sealed at the wellhead, test pressure is created inside the wellhead with a pressure rise rate of 0.3- 0.5 MPa / s, carry out technological exposure for at least 30 minutes, evaluate the pressure change, make a conclusion about the tightness or leaks of the wellhead valves, release pressure in the wellheads with a speed of not more than 1 MPa / s, unpack they pack the packer, drain the liquid above the packer into the well, remove the packer with the drive and the support pipe from the well at a speed of not more than 1 m / s.

These specific digital values are selected experimentally as the best for solving the task. At the same time, there are no failures and the greatest reliability of pressure testing of wellhead valves is ensured.

When carrying out specific work, wellhead fittings are mounted on the casing, for example, a preventer, valves, manometers, piping, etc. A device for crimping wellhead fittings shown in FIGS. 1 and 2 is lowered into the well.

Figure 1 shows a device for crimping wellhead fittings in a well, conventionally consisting of a device for packing and a device for crimping.

The packing device consists of a support pipe 1 having a through groove 2. A support plate 3, rubber cuffs 4 and 5, a washer 6, a clamping plate 7 and a pusher 8 are put on the support pipe 1 (see section AA in FIG. 2) passing through the groove 2 and centered in the clamping plate 7. The support pipe 1 is plugged with a plug 9, which also serves as a support for the support plate 3. In the upper part of the support pipe 1 there is an opening 10 to remove residual air in the valve. From the top of the pusher 8, a rod 11 is installed in the support pipe 1, which serves as a force transmission channel from the bolt 12 to the pusher 8. A nut 13 is connected to the support pipe 1 with a faceplate 14, which is being tested for wellhead fittings.

For crimping, use a packing device 15, a column head 16 with a faceplate 14, a column pipe 17 connected on one side to the column head 16 by a coupling 18, and on the other hand, from the casing of the well 19 by a coupling 20. The pipes 21 of the column head 16 are connected to the injection pump unit lines (not shown).

The packing device 15, screwed onto the faceplate 14, is lowered at a speed of not more than 1 m / s through the column head 16 and the column pipe 17 into the casing 19 so that the rubber cuffs 4 and 5 are below the connection of the casing 19 with the column pipe 17, and the faceplate 14 rested on the upper plane of the column head 16. After that, the faceplate 14 is fixed to the column head 16 using the studs 22. The studs 22 are not tightened. After that, tighten the bolt 12 with a torque of 200 N · m clockwise. The resulting axial force through the rod 11, the pusher 8 and the clamping plate 7 presses the rubber cuffs 5 and 4 to the support plate 3. The cuffs 5 and 4, in turn, elastically deformed, are pressed against the wall of the casing string 20, isolating the lower part of the casing string 19. The cut-off cavity above the cuffs 4 and 5 is filled through the discharge line with the process fluid and, then, with the pins 22, the faceplate 14 is pulled to the column head 16. This eliminates the air cushion inside the chamber during filling with liquid, thereby creating a closed the chamber inside the column pipe 17 and the column head 16. Through the discharge line of the pump unit create the required pressure test. The rate of pressure rise is 0.3-0.5 MPa / s. Carry out technological exposure for at least 30 minutes. Assess the change in pressure. Wellhead equipment is considered leakproof if the pressure drop does not exceed 5%. Make a conclusion about the tightness or leaks of wellhead valves. Relieve pressure at a rate of not more than 1 MPa / s along the discharge line. Unpack the packer by turning the bolt 12 counterclockwise, drain the process fluid into the casing 19, unscrew the studs 22 and remove the packer 15 together with the faceplate 14 from the well at a speed of not more than 1 m / s.

As a result, it is possible to determine the tightness of wellhead valves in the well with 100% certainty.

Concrete example

Pressure testing of wellhead valves is carried out in an oil well. The well has a casing with a diameter of 146 mm. A device for crimping the preventer according to FIGS. 1 and 2 is mounted on the well.

Make the descent of the packing device 15 with the drive on the support pipe 1 at a speed of 0.9 m / s. The well above the cuffs 4 and 5 is filled with water, the support pipe 1 is sealed at the wellhead, test pressure is created inside the wellhead through the nozzles 21 with a pressure rise rate of 0.4 MPa / s, technological exposure is carried out for 30 minutes, it is determined that the pressure is not changed, evaluate the pressure change, make a conclusion about the tightness of the wellhead fittings, release the pressure in the wellhead fittings at a speed of 0.9 MPa / s, unpack the packer 15, drain the water over the packer into the casing 19, remove the packer e means 15 with the drive and support tube 1 from the wellbore at a rate not more than 0.9 m / s.

As a result, it is possible to determine with complete accuracy the tightness of the wellhead reinforcement in the well.

The application of the proposed method will improve the reliability of determining the tightness of wellhead valves during crimping.

Claims (1)

A method of crimping wellhead fittings in a well, including lowering the packer with the drive on the support pipe into the well, setting the packer and creating pressure, characterized in that the descent of the packer with the drive on the support pipe is carried out at a speed of not more than 1 m / s, the well above the packer is filled with liquid the support pipe is sealed at the wellhead, test pressure is created inside the wellhead with a pressure rise rate of 0.3-0.5 MPa / s, the process is held for at least 30 minutes, the pressure change is assessed, a conclusion is made about the tightness of the wellhead or leaks of the wellhead reinforcement, depressurize the wellhead armature at a speed of not more than 1 MPa / s, unpack the packer, drain the liquid above the packer into the well, remove the packer with the drive and support pipe from the well at a speed of not more than 1 m / s.

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